Cellular wireless systems typically employ a base station at the center of each cell which provides service to users within that cell. In order to increase the converge area of a given base station, it has been proposed to introduce a relay function within the conventional cellular network. This will allow the extension of the network to a multi-hop network topology in which some mobile users would communicate with the network via the relay function and then the base station.
The conventional relay technology that is available includes analogue relays and digital relays both of which come in the form of external band relays. The available analogue relays require dual RF transceiver chains, and in-band relays which suffer from noise amplification and feedback isolation problems and requires very stringent transmit to receive isolation. The available digital FDD (Frequency Division Duplex) relays require dual RF (Radio Frequency) transceiver chains. TDD (Time Division Duplex) in-band relays can be implemented with one receiver chain.